In the case of electrical appliances which are used in severe operating conditions, precautions must be taken to ensure that the electrical switch is protected against damaging influences which may adversely affect its serviceability. For example, such damaging influences may be exposure to moisture, dust or the like. This applies particularly to switches which are used in appliances for building technology, agriculture, building trade, or the like.
One such electrical switch is known from DE 197 05 068 A1. The switch has a housing with a contact system which is located in the interior of the housing. The operating member is in the form of a rocker, which is arranged on the housing such that it can move, and is used for the switching action on the contact system, with an opening being provided in the housing, for the switching action of the operating member. For sealing, the opening is provided with an elastic seal which is attached to the housing.
The contact system of this known switch has a switching contact which is mounted so that it can pivot, and on which the operating member acts by means of a central plunger, for switching. The central plunger is attached to the operating member and projects through the opening into the interior of the switch. The seal, which is attached to the housing and comprises a bellows or an O-ring, also rests on the plunger. However, it has been found that harmful substances, for example water, can migrate into the interior of the housing between the plunger and the seal, and thereby adversely affect the serviceability of the switch.